The Drug Induced Liver Injury Network (DILIN), sponsored by NIDDK was established in 2003 to identify cases of DILI across a diverse demographic and geographic spectrum. Mount Sinai has been an integral part of the DILIN since 2013 and helped the network increase recruitment such that patient accrual now exceeds expectations. The current 6 clinical sites have performed very well, with Mount Sinai among the leading enrolling sites, particularly for acute DILI cases. The integration of several new hospitals to the Mount Sinai Health System and formation of a Liver Institute to organize hepatology care across the health system will likely result in an increase in enrollment from the Mount Sinai DILIN site with added ethnic diversity. As a whole, the DILIN is well positioned to embark on important goals: continuing to recruit patients early in the course of illness to identify DILI biomarkers; increase the racial/ethnic diversity of patients in the prospective cohort by focused recruitment in urban areas; enrollment of herbal and dietary supplement (HDS) cases along with analysis of HDS products collected in the repository; setting up systems for early detection of drugs or HDS associated with DILI to assist regulatory authorities; and continuing to provide accurate clinical information about DILI through published literature and support for the Livertox website. The Specific Aims for the Mount Sinai site are as follows: 1) To enroll adults and children with DILI in the current DILIN prospective and retrospective databases; 2) To specifically enroll patients early in the course of suspected DILI; 3) To enrich the current DILIN prospective and retrospective databases with patients of non-Caucasian ethnicity; 4) To evaluate serum and genetic biomarkers for chemotherapy-induced liver injury and determine if melatonin pretreatment prevents chemotherapy-induced liver injury; and 5) To rapidly identify newly approved prescription medications and new HDS formulations that cause unexpected concentrations of DILI cases.